it's an easy problem to solve. get right behind him, keep your kite low, wait for him to do a transition and act all surprised when he has to kite wayyy downwind to get around you.

it's funny, the opposite rules apply at the lower launch. if you kite in there and just mow the lawn, you'll get angry looks too. i don't mind people doing crazy stuff and crashing their kite, but nothing annoys me more than someone who just rides in there and turns around. what a waste!